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/*!
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\example examples/boxplotchart
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\title Box and Whiskers Example
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\subtitle
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The example shows how to create a box-and-whiskers chart. It also shows how to read the non-continuous data from the file,
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arrange it and find medians needed for box-and-whiskers plotting.
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\image examples_boxplotchart.png
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To show the share deviation of two companies we start by creating two QBoxPlotSeries to handle monthly data.
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\snippet ../examples/boxplotchart/main.cpp 1
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QFile class is used to open a text file where the non-continuous data is kept. The BoxDataReader is an auxiliary class for
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reading the text file and finding the extreme and median values from the data. The BoxDataReader is explained in more detail later.
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The method readBox reads the values and sets them to the QBoxSet item which the method returns for the caller. The returned QBoxSet
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item is added to the series.
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\snippet ../examples/boxplotchart/main.cpp 2
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In this section a second file is opened for reading the data for the second company.
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\snippet ../examples/boxplotchart/main.cpp 3
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In this code snippet a new QChart instance is created and previously created series are added to it. Also title is defined and
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animation is set to be SeriesAnimation.
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\snippet ../examples/boxplotchart/main.cpp 4
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Here we ask chart to create default axes for our presentation. We also set range for vertical axis by querying the pointer
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for the axis from the chart and then setting the min and max for that axis.
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\snippet ../examples/boxplotchart/main.cpp 5
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In this section we set legends visible and place them at the bottom of the chart.
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\snippet ../examples/boxplotchart/main.cpp 6
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Finally we add the chart onto a view. We also turn on the antialiasing for the chartView.
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\snippet ../examples/boxplotchart/main.cpp 7
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The chart is ready to be shown. We set the chart to be central widget of the window.
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We also set the size for the chart window and show it.
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\snippet ../examples/boxplotchart/main.cpp 8
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Here the method readBox is explained in detail. Firstly a line is read from the file and lines starting with # are rejected
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since they are considered as comment lines.
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\snippet ../examples/boxplotchart/boxdatareader.cpp 1
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On the file the data is arranged as number, space, number, space and so on. On this snippet the line is split into single number strings which
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are stored on QStringList.
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\snippet ../examples/boxplotchart/boxdatareader.cpp 2
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The sortedList will hold the numbers in continuous order and in this code segment we show how to do it. First the sortedList is cleared and numbers
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are read from the strList and stored into sortedList in double format. The qSort method arranges the sortedList into continuous order
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starting from the smallest.
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\snippet ../examples/boxplotchart/boxdatareader.cpp 3
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Here is a code sample how to select extremes and medians from the continuous data. Firstly a new QBoxSet is created.
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Lower and upper extremes are simple to select; they are just first and last items on the sortedList. For medians we use a helper
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method findMedian which is explained later. For the median from the upper half we need to adjust the begin number if
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amount of the numbers is even or uneven. The end number for lower half comes naturally from int rounding.
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\snippet ../examples/boxplotchart/boxdatareader.cpp 4
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Here's the code sample for the method findMedian. If the amount of numbers is uneven we select the number from
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the middle. For even amount numbers we take two numbers from the middle and calculate the mean value.
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\snippet ../examples/boxplotchart/boxdatareader.cpp 5
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*/
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